T M
class Date
Error ReportCollection examples

Calendar date

class Date { }

A Date is an immutable object identifying a day in the Gregorian calendar.

Date objects support addition and subtraction of integers, where an integer is interpreted as the number of days. You can compare Date objects with the numeric comparison operators ==, <, <=, >, >=, != . Their stringification in YYYY-MM-DD format means that comparing them with the string operators eq, lt, le etc. also gives the right result.

Date.today creates an object the current day according to the system clock.

my $d = Date.new(20151224); # Christmas Eve! 
say $d;                         # OUTPUT: «2015-12-24␤» 
say $d.year;                    # OUTPUT: «2015␤» 
say $d.month;                   # OUTPUT: «12␤» 
say $d.day;                     # OUTPUT: «24␤» 
say $d.day-of-week;             # OUTPUT: «4␤» (Thursday) 
say $d.later(days => 20);       # OUTPUT: «2016-01-13␤» 
my $n = Date.new('2015-12-31'); # New Year's Eve 
say $n - $d;                    # OUTPUT: «7␤», 7 days between New Years/Christmas Eve 
say $n + 1;                     # OUTPUT: «2016-01-01␤»

Note since version 6.d, .raku can be called on Date. It will also reject synthetic numerics such as 7̈ .

Methods

method new

Defined as:

multi method new($year$month$day:&formatter --> Date:D)
multi method new(:$year!:$month = 1:$day = 1  --> Date:D)
multi method new(Str $date                        --> Date:D)
multi method new(Instant:D $dt                    --> Date:D)
multi method new(DateTime:D $dt                   --> Date:D)

Creates a new Date object, either from a triple of (year, month, day) that can be coerced to integers, or from a string of the form YYYY-MM-DD (ISO 8601), or from an Instant or DateTime object. Optionally accepts a formatter as a named parameter.

my $date = Date.new(204211);
$date = Date.new(year => 2042month => 1day => 1);
$date = Date.new("2042-01-01");
$date = Date.new(Instant.from-posix: 1482155532);
$date = Date.new(DateTime.now);

method new-from-daycount

Defined as:

method new-from-daycount($daycount,:&formatter --> Date:D)

Creates a new Date object given $daycount which is the number of days from epoch Nov. 17, 1858, i.e. the Modified Julian Day. Optionally accepts a formatter as a named parameter.

say Date.new-from-daycount(49987);          # OUTPUT: «1995-09-27␤»

method last-date-in-month

Defined as:

method last-date-in-month(Date:D: --> Date:D)

Returns the last date in the month of the Date object. Otherwise, returns the invocant if the day value is already the last day of the month.

say Date.new('2015-11-24').last-date-in-month# OUTPUT: «2015-11-30␤»

This should allow for much easier ranges like

$date .. $date.last-date-in-month

for all remaining dates in the month.

method first-date-in-month

Defined as:

method first-date-in-month(Date:D: --> Date:D)

Returns the first date in the month of the Date object. Otherwise, returns the invocant if the day value is already the first day of the month.

say Date.new('2015-11-24').first-date-in-month# OUTPUT: «2015-11-01␤»

method clone

Defined as:

method clone(Date:D: :$year:$month:$day:&formatter)

Creates a new Date object based on the invocant, but with the given arguments overriding the values from the invocant.

say Date.new('2015-11-24').clone(month => 12);    # OUTPUT: «2015-12-24␤»

method today

Defined as:

method today(:&formatter --> Date:D)

Returns a Date object for the current day. Optionally accepts a formatter named parameter.

say Date.today;

method truncated-to

Defined as:

method truncated-to(Date:D: Cool $unit)

Returns a Date truncated to the first day of its year, month or week. For example

my $c = Date.new('2012-12-24');
say $c.truncated-to('year');     # OUTPUT: «2012-01-01␤» 
say $c.truncated-to('month');    # OUTPUT: «2012-12-01␤» 
say $c.truncated-to('week');     # OUTPUT: «2012-12-24␤», because it's Monday already

method succ

Defined as:

method succ(Date:D: --> Date:D)

Returns a Date of the following day. "succ" is short for "successor".

say Date.new("2016-02-28").succ;   # OUTPUT: «2016-02-29␤»

method pred

Defined as:

method pred(Date:D: --> Date:D)

Returns a Date of the previous day. "pred" is short for "predecessor".

say Date.new("2016-01-01").pred;   # OUTPUT: «2015-12-31␤»

method Str

Defined as:

multi method Str(Date:D: --> Str:D)

Returns a string representation of the invocant, as specified by the formatter. If no formatter was specified, an (ISO 8601) date will be returned.

say Date.new('2015-12-24').Str;                     # OUTPUT: «2015-12-24␤» 
 
my $fmt = { sprintf "%02d/%02d/%04d".month.day.year };
say Date.new('2015-12-24'formatter => $fmt).Str;  # OUTPUT: «12/24/2015␤»

method gist

Defined as:

multi method gist(Date:D: --> Str:D)

Returns the date in YYYY-MM-DD format (ISO 8601)

say Date.new('2015-12-24').gist;                    # OUTPUT: «2015-12-24␤»

method Date

Defined as:

method Date(--> Date)

Returns the invocant.

say Date.new('2015-12-24').Date;  # OUTPUT: «2015-12-24␤» 
say Date.Date;                    # OUTPUT: «(Date)␤»

method DateTime

Defined as:

multi method DateTime(Date:U --> DateTime:U)
multi method DateTime(Date:D --> DateTime:D)

Converts the invocant to DateTime

say Date.new('2015-12-24').DateTime# OUTPUT: «2015-12-24T00:00:00Z␤» 
say Date.DateTime;                   # OUTPUT: «(DateTime)␤»

Functions

sub sleep

sub sleep($seconds = Inf --> Nil)

Attempt to sleep for the given number of $seconds. Returns Nil on completion. Accepts Int, Num, Rat, or Duration types as an argument since all of these also do Real.

sleep 5;                # Int 
sleep 5.2;              # Num 
sleep (5/2);            # Rat 
sleep (now - now + 5);  # Duration 

It is thus possible to sleep for a non-integer amount of time. For instance, the following code shows that sleep (5/2) sleeps for 2.5 seconds and sleep 5.2 sleeps for 5.2 seconds:

my $before = now;
sleep (5/2);
my $after = now;
say $after-$before;  # OUTPUT: «2.502411561␤» 
 
$before = now;
sleep 5.2;
$after = now;
say $after-$before;  # OUTPUT: «5.20156987␤»

sub sleep-timer

sub sleep-timer(Real() $seconds = Inf --> Duration:D)

This function is implemented like sleep, but unlike the former it does return a Duration instance with the number of seconds the system did not sleep.

In particular, the returned Duration will handle the number of seconds remaining when the process has been awakened by some external event (e.g., Virtual Machine or Operating System events). Under normal condition, when sleep is not interrupted, the returned Duration has a value of 0, meaning no extra seconds remained to sleep. Therefore, in normal situations:

say sleep-timer 3.14;  # OUTPUT: «0␤»

The same result applies to edge cases, when a negative or zero time to sleep is passed as argument:

say sleep-timer -2# OUTPUT: 0 
say sleep-timer 0;  # OUTPUT: 0 

See also sleep-until.

sub sleep-until

sub sleep-until(Instant $until --> Bool)

Works similar to sleep but checks the current time and keeps sleeping until the required instant in the future has been reached. It uses internally the sleep-timer method in a loop to ensure that, if accidentally woken up early, it will wait again for the specified amount of time remaining to reach the specified instant. goes back to sleep

Returns True if the Instant in the future has been achieved (either by mean of sleeping or because it is right now), False in the case an Instant in the past has been specified.

To sleep until 10 seconds into the future, one could write something like this:

say sleep-until now+10;   # OUTPUT: «True␤»

Trying to sleep until a time in the past doesn't work:

my $instant = now - 5;
say sleep-until $instant# OUTPUT: «False␤»

However if we put the instant sufficiently far in the future, the sleep should run:

my $instant = now + 30;
# assuming the two commands are run within 30 seconds of one another... 
say sleep-until $instant# OUTPUT: «True␤» 

To specify an exact instant in the future, first create a DateTime at the appropriate point in time, and cast to an Instant.

my $instant = DateTime.new(
    year => 2020,
    month => 9,
    day => 1,
    hour => 22,
    minute => 5);
say sleep-until $instant.Instant# True (eventually...) 

This could be used as a primitive kind of alarm clock. For instance, say you need to get up at 7am on the 4th of September 2015, but for some reason your usual alarm clock is broken and you only have your laptop. You can specify the time to get up (being careful about time zones, since DateTime.new uses UTC by default) as an Instant and pass this to sleep-until, after which you can play an mp3 file to wake you up instead of your normal alarm clock. This scenario looks roughly like this:

# DateTime.new uses UTC by default, so get time zone from current time 
my $timezone = DateTime.now.timezone;
my $instant = DateTime.new(
    year => 2015,
    month => 9,
    day => 4,
    hour => 7,
    minute => 0,
    timezone => $timezone
).Instant;
sleep-until $instant;
qqx{mplayer wake-me-up.mp3};

sub infix:<->

multi sub infix:<-> (Date:DInt:D --> Date:D)
multi sub infix:<-> (Date:DDate:D --> Int:D)

Takes a date to subtract from and either an Int, representing the number of days to subtract, or another Date object. Returns a new Date object or the number of days between the two dates, respectively.

say Date.new('2016-12-25'- Date.new('2016-12-24'); # OUTPUT: «1␤» 
say Date.new('2015-12-25'- Date.new('2016-11-21'); # OUTPUT: «-332␤» 
say Date.new('2016-11-21'- 332;                    # OUTPUT: «2015-12-25␤»

sub infix:<+>

multi sub infix:<+> (Date:DInt:D --> Date:D)
multi sub infix:<+> (Int:DDate:D --> Date:D)

Takes an Int and adds that many days to the given Date object.

say Date.new('2015-12-25'+ 332# OUTPUT: «2016-11-21␤» 
say 1 + Date.new('2015-12-25');   # OUTPUT: «2015-12-26␤»